A round pipe is flexible. And imagine if you had a 1/4 mile string of 3 1/2" pipe laying flat on the ground and you tied on end to a tree and the other to a tractor. You could easily pull it back around to itself in a circle. That is pretty much what happens in a well. The accidental 20 degree deviation in MJ#1 could easily be cause by excessive down pressure causing the pipe to flex and sending it off course. Remember Dustin stated "it's was like drilling with a string of spaghetti" Pipe is flexible and when ya got 3 miles of it, wow like spaghetti flexible.